ctypesArgumentError when calling cvCalibrateCamera2

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What steps will reproduce the problem?
1. find chessboardcorners with cvFindChessboardCorners()
2. try to calibrate camera with cvCalibrateCamera2()
3.

What is the expected output? What do you see instead?
I expected camera intrinsics and distortion coeffs returned. Instead, I 
got:
ctypes.ArgumentError: argument 1: <type 'exceptions.TypeError'>: Don't 
know how to convert parameter 1

What version of the product are you using? On what operating system?
OpenCV 1.0 with ctypes-opencv 0.7.2 on Windows XP

Please provide any additional information below.
Actually this is rather weird because I could calibrate camera without a 
problem last time. I was calling calibrate camera in a window method, and 
then decided to make my own camera class which has calibration-related 
methods in it. However, the error message implies that I passed a 
parameter of wrong type. Argument 1, object_points, should be cvMat, which 
it exactly is. This is full traceback message:

Traceback (most recent call last):
  File "D:\workspace\Doonoon\gui\Doonoon_frame.py", line 383, in Calibrate
    cam.calibrate()
  File "D:\workspace\Doonoon\gui\Doonoon_frame.py", line 161, in calibrate
    ( intrinsic, distortion ) = cvCalibrateCamera2( byref
(self.object_points), self.image_points, self.point_counts, cvGetSize( 
img ), self.intrinsic_matrix, self.distortion_coeffs, None, None, 0 )
ctypes.ArgumentError: argument 1: <type 'exceptions.TypeError'>: Don't 
know how to convert parameter 1

This is what I got when I print argument 1 (objects_points)

CvMat
(type=1111638021,step=12,refcount=66116416,hdr_refcount=1,data=<opencv.cxco
re.CvMatData object at 0x0236FD50>,r=<opencv.cxcore.CvMatRows object at 
0x0236FB70>,c=<opencv.cxcore.CvMatCols object at 0x0236FE40>)

This is the code in which the matrices are generated and used:

    self.intrinsic_matrix  = cvCreateMat( 3, 3, CV_32FC1 )
    self.distortion_coeffs = cvCreateMat( 4, 1, CV_32FC1 )
    self.point_counts      = cvCreateMat( self.n_boards, 1, CV_32SC1 )
    self.image_points      = cvCreateMat( self.n_boards * self.board_n, 2, 
CV_32FC1 )
    self.object_points     = cvCreateMat( self.n_boards * self.board_n, 3, 
CV_32FC1 )
    ...
    ...
      for j in range( self.board_n ):
        #print i, j
        self.image_points[i,0] = corners[j].x
        self.image_points[i,1] = corners[j].y
        self.object_points[i,0] = j / self.board_w
        self.object_points[i,1] = j % self.board_w
        self.object_points[i,2] = 0.0
        i+= 1
        j+= 1
      self.point_counts[self.success_count,0] = self.board_n
    ...
    ...
    self.intrinsic_matrix[0,0] = 1.0
    self.intrinsic_matrix[1,1] = 1.0
    ( intrinsic, distortion ) = cvCalibrateCamera2( self.object_points, 
self.image_points, self.point_counts, cvGetSize( img ), 
self.intrinsic_matrix, self.distortion_coeffs, None, None, 0 )

Sound like a troubleshooting than an issue. Sorry for that. Thanks.

Original issue reported on code.google.com by jikhan.j...@gmail.com on 8 Mar 2009 at 7:13

[GoogleCodeExporter]

Ummm.. my bad. It was not cvCalibrateCamera2() that caused the error. I handed 
wrong 
type of image (PIL image) to cvGetSize() function. 

Original comment by jikhan.j...@gmail.com on 20 Mar 2009 at 10:49

[GoogleCodeExporter]

Glad to know you have fixed the issue. Sorry I couldn't have helped earlier. I 
am
still busy with work these days.

Original comment by pmtri80@gmail.com on 25 Mar 2009 at 1:12

• Changed state: Fixed